Salts of organic di-thiophosphates



Patented Jan. 3, 1933 runwro .r. cnnrsrmann, or JERSEY UNITED STATES PATENT OFFICE CITY, NEW JERSEY,

ASSIGNOR J30 AMERICAN oymmm comrm, or NEW YORK, n. Y., A coarona'non or 1mm -SAL'1S or oaemrc m-rmornosrm'ms No Drawing.

This invention relates to fiotation agents. These agents are particularlyapplicable for facilitating the froth flotation and mineral separation of sulphide ores and the like.

As described in m co-pending application Serial No. 235,121, led November 22, 1927, of which the present application is a continuation in part, it has been found that a series of compounds formed by the reaction of phosphorous pentasulphide on certain organic compounds, such as the alcohols and other hydroxy bodies, have properties which adapt them for use as flotation agents. As

described in that application, the compounds prepared are probably organic dithio-phosphates.

I have further discovered that the alkali- Th forming metal salts of the organic di-thiophosphoric acids are also .valuable as flotation agents. More particularly I utilize the compounds derived from the alcohols of the alkyl series, and preferably from those alkyl alcohols containing from two to eight carbon atoms. The compounds forming the present invention most probably have the following structural formula:

vwherein R indicates an or anic rou e. g., an alkyl group, and alkali-forming metal.

The flotation agents described may be prepared in any suitable manner such as that set forth in application Serial N 0. 235,121 which describes the preparation of di-iso-propyl dithio-phosphate, although the invention is not limited to the described method. The alkali-forming metal salts may also be prepared in any desirable manner. For instance, to prepare the sodium di-iso-propyl di-thiophosphate a suitable quantity of soda ash is charged into a mixer. The di-iso-propyl dithio-phosphate (di-iso-propyl di-thio-phosphoric acid) is then added slowly to the charge in the mixer. The mixer is preferably of the jacketed type to permit cooling X represents an of the batch during addition of the acid and Application filed October-22, 1928. Serial No. 814,338.

products. It was found that better results could be obtained by slowly adding about of the desired quantity of acid, removing and drying the mixture, and after replacmg the same in the mixer, slowly adding the remainder of the acid. The resultant mixture is then removed and finally dried, giving a white or bufi colored powder containing a high percentage of sodium di-iso-propyl dithlo-phosphate, with or without an excess of soda ash.

As another example, I may prepare the diethyl di-thio-phosphoric acid by reacting upon208 poundsof anhydrous ethyl alcohol with 248 pounds of phosphorous pentasulphide (91 %P S,;) crushed to passafour-mesh screen. e reaction is preferably carried out in a glass lined kettle provided with an aluminum reflux condenser. The alcohol is charged into the kettle, heated to 35 C. and the phosphorous pentasulphide added slowly through a suitable feed pipe.

Since the reaction is exothermic, care is used to add the phosphorous pentasulphide at such a rate as to prevent undue rise in tem-' perature, cooling means being used if neces sary. The temperature is kept below 85 C. and preferably around 45 C. during the mixing of the ingredients which takes a period of about 1 hours. The temperature of the mix is then raised to about 85 C. and maintained at about that point for 2 to 3 hours after which the products are allowed to cool and the di-ethyl di-thio-phosphoric acid is removed. The crude acid obtained weighs over 400 pounds and contains about 88% pure acid. The alkali-forming metal salts of the crude or purified acid may be prepared as previously described for the di-iso-propyl dithio-phosphate.

. In place of the alcohols used as described above, I may utilize various organic substances such as other alcohols of the alkyl series, and particularly those alkyl alcohols containing 2 to 8 carbon atoms. As a suitable alkaliforming metal or base, I may use salts, oxides or hydroxides of the various alkali metals or alkali earth metals to prepare the corresponding substituted phosphates forming the subject of the present invention. The term alkali-forming metal is used to cover the alkali metals (including ammonium) and alkali earth metals. In place of phosphorous pentasulphide, it is possible to' use equivalent phosphorous sulphides or mixtures of the same, susbtantially all of which contain more'or less phosphorous pentasulphide.

The alkaline metal organic di-thio-phosphates prepared as above described or in any other suitable manner, are excellent flotation agents and are markedly superior to many of the agents in ordinary use, particularly when employed for facilitating the froth flotation of sulphide ores.

Although I have described but a few; specific examples of my invention, I consider the same not to be limited to the specific substances mentioned, but to include various other compounds of similar constitution as set forth in the claims appended hereto. It is understood that any suitable changes and variations may from the spirit and scope of the invention.

I claim:

1. A solid salt comprising substantially wholly a compound having most probably the following structural formula:

no P s no s-x in which X is an alkali-forming metal and R represents an alkyl rad'cal.

3. A solid salt comprising substantially wholly a compound having most probably the following structural formula:

in which X is an alkali-forming metal and R represents an alkyl radical having from 2 to 8 carbon atoms.

4. A solid salt comprising wholly a compound having most probably the following structural formula:

wholly an alkali-forming metal di-ethyl dithio-phosphate.

wholly an alkali metal solid salt comprising substantially I di-thio-phosphate. solid salt comprising substantially di-thio-phosphate.

In testimony whereof, I have hereunto subscribed my name this 18 day of October,

be made without departing I substantially I I LUDWIG J. CHRISTMANN. 

